As Secretary of State Rex Tillerson arrives in Moscow to meet with Russian foreign officials, including President Vladimir Putin, the White House is elevating its rhetoric on the recent chemical attack in Syria, in which Turkish investigators recently confirmed sarin gas was used.

The White House said Tuesday that the Russian government tried to cover up the chemical attack and create confusion about it through spreading misinformation to try and shield the Assad regime.

Shortly before he boarded a plane for the Russian capital, he cautioned that Syrian President Bashar al-Assad’s regime is coming to an end. The White House has at times echoed that sentiment, as did UN Ambassador Nikki Haley, though Tillerson himself on several of the Sunday talk shows downplayed the idea that the U.S.’s Syria strategy was changing to focus on Assad, saying instead that it would remain the removal from ISIS.

What can we expect Tillerson to get out of this meeting? What should the U.S.’s role be moving forward in terms of foreign policy? How should it work with allies on sanctions?